How a Starter Motor Works
The starter motor has an important job: it turns the engine on when you start your car, so other parts can work properly. When you turn the ignition key, the starter motor starts working and turns the engine. This helps the engine take in air.
There is a flywheel on the engine. It has a ring gear around its edge and is connected to the end of the crankshaft. On the starter motor, there is a pinion that fits perfectly into the grooves of the ring gear.
When you turn the ignition switch, the electromagnet inside the starter motor works. It pushes out a rod, and the pinion is attached to this rod. The pinion then connects with the flywheel, and the starter motor begins to spin. This spinning turns the engine, which then takes in air and fuel.
Once the engine starts running, the starter motor stops working. The electromagnet shuts off, and the rod pulls back into the starter motor. This moves the pinion away from the flywheel, so it does not get damaged.
Starter Motor components & their functions
Armatuur
The armature is an electromagnet, mounted on the drive shaft and bearings for support. It is a laminated soft iron core which is wrapped with numerous conductors loops or windings.
Commutator
The commutator is a section of the shaft at the rear of the housing on which the brushes run to conduct electricity. The commutator is made up of two plates attached to the axle of the armature. These plates provide the two connections for the coil of the electromagnet.
Borstels
The brushes run on a section of the commutator at the rear of the housing, making contact with the contacts of the commutator and conducting electricity.
Magneet
The solenoid contains of two coils of wire that are wrapped around a moveable core. The solenoid acts as a switch to close the electrical connection and connects the starter motor to the vehicle’s battery.
Plunger
The plunger works by using the connected vehicle battery and the solenoid to push the plunger forward, which engages the pinion.
Lever Fork
The lever fork is connected to the plunger so when the plunger is pushed forwards, so is the lever fork. This process then activates the pinion.
Pinion
The pinion is a unique combination of a gear and springs. Once the starter is engaged the gear is extended into the gearbox housing and is engaged with the flywheel. This spins the engine to begin the combustion process.
Field Coils
The housing holds the starter fields in the housing with screws. This can consist of two to four field coils connected in series. Energised by the battery this converts the coils into an electromagnet which then turns the armature. When the armature coils are powered a magnetic field is created around the armature.